I want to drive a 60 watt 24volt heating element of a 24volt 80 watt transformer. The trigger pin will be connected on a comparator that is capable of sinking up to 18 mA of current. I know that the ideal circuit for the job would be circuit 4 yet the MOC30xx family of triac drivers is incapable of handling 90 mA of current in order to latch the main triac. Moreover, i got 4 optocouplers and again none of them can handle 90mA of current.
Which circuit do you suggest i use? (i was going to go with circuit 1 to be honest)
Is there a better way of getting the job done?
Do you know any other triac drivers capable of handling such currents?
Last question is a bit off topic:
Which would be the best way to switch ac current?
Triac
Full wave rectifier and a MOSFET (Tried it and the power wasted in the diodes of the full wave rectifier is huge)
2 MOSFETs connected source to source and the drain terminals connected to the AC(Tried it and destroyed 2 MOSFETs one after the other by unknown cause {note: the MOSFETs were at all times cool, no magic smoke was released in any case} Still haven't figured out why they got destroyed as the circuit was correct at all times. After disconnecting the MOSFETs and measuring them out, some of their pins would be shorted, in one case the gate with drain showing 0 resistance or the drain with source showing 0 resistance. Do you have any idea why this might have happened? {The circuit is shown in one of the pictures. The MOSFETs are IRF630MFP with a max gate voltage of +- 20V})
I am really sorry for the crappy pictures. I know i need to change my mobilephone.
Regards
Void